System and apparatus for controlling electric motors.



N. W. STORER &A. .I. HALL SYSTEM AND APPARATUS FOR CONTROLLING ELECTRIC MOTORS. APPLICATION FILED saw-27.1916.

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N. W. STORER 8 A. J. HALL. SYSTEM AND APPARATUS FOR CONTROLLING ELECTRIC MOTORS.

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ATTORNEY UNITED STATES PATENT OFFICE.

NORMAN W. STORER, OF PITTSBURGH, AND ARTHUR J. HALL, OF WILKINSBURG, PENN- SYLVANIA, ASSIGNORS TO WESTINGHOUSE ELECTRIC AND PANY,'A CORPORATION OF PENNSYLVANIA.

MANUFACTURING COM- SYSTEM AND APPARATUS FOR CONTROLLING ELECTRIC MOTORS.

Original application filed October 5, 1912, Serial No. 724,063.

To all whom it may concern:

Be it known that we, NORMAN V. S'ronnn, a citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, and AR- THUR J. HALL, a subject of the King of Eng land, resident of lVilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Systems and. Apparatus for C011- trolling Electric Motors, of which the following specification is a division of application Serial No. 724,063, filed October 5, 1912.

,Our invention relates to systems and ap paratus for controlling electric motors, and it has special reference to power-actuated drum controllers and systems embodying the same.

One object of our invention is to provide a relatively simple and compact mechanism for actuating controllers of the drum type that shall be adapted to replace the usual cover and motormens handles of present manually operated railway controllers, and the operation of which is governed by a small master controller.

Another object of our invention is to provide a controller actuating device of the character above indicated which shall be so constructed and arranged as to permit of its operation and use, either singly or in multiple with others, forcontrolling the operation of either single cars or trains composed of any number of cars.

Another object of our invention is to provide a fluid-operated controller drum which may be positively actuated in a series of distinct and definite steps through the agency of an operating cylinder and a movable piston upon the opposite sides of which relatively high balanced pressures are normally maintained for the purpose of holding the piston at rest, it being necessary only to reduce the pressure onone side of said piston in order to effect an unbalancing of pressures and a consequent movement of the piston. in the one direction or' the other until balanced pressures are restored.

A well known type of controller for railway motors comprises a main drum that is rotatable for the purpose of governing the Specification of Letters Patent.

Patented June 12, 191'7.

Divided and this application filed September Serial No. 122,383.

motor circuits and the value of the accelerating resistance, and a reverse drum that is adapted to occupy the one or the other of two positions, according to the desired direction of rotation of the motor armatures. The drums are provided with star wheels and pawls or similar devices for accentuating the various control positions, and the drum shafts extend through holes in the cover of the controller so that they may be turned by means of suitable handles. However, cars equipped with controllers of this character cannot be operated in trains and controlled from the front end only, since the controllers must be separately and manually operated.

According to our present invention, we provide what we shall hereinafter term an operating head which constitutes a unitary structure that may be removably secured to any ordinary drum controller and is adapted to actuate the main drum of the controller either step-bystep or continuously, and also to operate the reverse drum. The controllers and their associated operating heads may be located under the cars, and the operation thereof governed by means of a master controller and a suitable remote control auxiliary system which may conveniently be of the multiple unit type.

In a co-pending application, Serial No. 724,065, filed October 5, 1912, by A. J. Hall and L. G. Riley, and assigned to the VVestinghouse Electric and Manufacturing Company, a somewhat'similar control system is disclosed which embodies a fliilid-operated controller drum that is adapted to be actuated through a series of steps in accordance with the manipulation of a master controller, which, in turn, governs the operation of a plurality of electro-magnetically controlled valves that are associated with the opposite ends of an operating cylinder. This fluid-actuated device, however, is so constructed and arranged as to be actuated by merely admitting an operating fluid to one side of its movable piston, and its movement is arrested by releasing the operating fluid and thus permitting the reestablishment of balanced atmospheric pressures acting upon the piston.

An appreciable time interval is necessarily required to effect the exhaust of operating fluid, during which period, the inertia of the moving piston and associated parts may cause it to over-shoot its proper position, while the operating fluid released is entirely wasted. In order to resume the operation, a complete new charge of fluid is required which becomes effective only when a material pressure has been built up which consumes an appreciable element of time. Moreover, in case it is desired to reverse the direction of operation, it becomes necessary to discharge the fluid from one side of the piston in order to bring .it to rest and, subsequently, to admit operating fluid to the opposite side thereof, which results in the loss of a material quantity of operating fluid. Furthermore, a relativelylarge amount of time is required which renders the operation correspondingly slow and less sensitive.

According to our present invention, however, balanced pressures are normally maintained on both sides of the piston and, therefore, movement in either direction may be effected quickly merely by opening the exhaust valve on one side thereof to permit the escape or reduction in pressure of the operating fluid. As soon as the pressure on one side has been reduced a comparatively small amount, the unbalanced pressures acting upon the piston are sufficient to cause the movement thereof. Only a relatively small amount of operating fluid therefore is wasted, while the operation of the apparatus is quickly responsive. In order to arrest the movement of the piston, it is only necessary to supply a small additional amount of operating fluid "to the low-pressure side, thereby establishing balancedpressure relations and positively and definitely bringing the piston to rest. Our present invention, therefore, has the advantages of economy of operating fluid which is utilized at a relatively high average pressure and, therefore, serves to produce a quick and sensitive operation of the control drum which is positively stopped in any position and is substantially dead beat.

Figure 1 of the accompanying drawings is a plan view, with the cover removed, of a controller operating head which forms a part of our invention. Fig. 2 is a view in side elevation and in section of the operating head of Fig. 1 and the upper portion of a controller with which the head is associated. Figs. 3 and i are sectional detail views, on a larger scale, of the valves which form parts of the operating head shown in the other figures. Figs. 5 and 6 are respectively a diagrammatic view of the control circuits and a diagran'imatic view of the motor circuits of a system embodying our invention.

Referring to Figs. 1 to 1, inclusive, of the drawings, the stri'icture here shown comprises an operating head 1, a controller of the well known type having a casing 2, a main drum 3, a reversing drum t, and suitable control fingers associated with each drum.

The operating head 1 comprises a base plate 5, which constitutes the cover of the casing 2, a pair of cylinders (S and 7, pistons 8 and 9 operating therein, a. connecting rod 10 for the pistons having a rack upon one side for actuating the main drum 3 of the controller, electromagnetically actuated valves 11 and 12 for controlling the supply of compressed air to the cylinders 6 and 7, cylinders 13 and 1a, pistons 15 and 16, a connecting rod 17 for the pistons 15 and 16 adapted to actuate the reverse drum -l, electromagnetically controlled valves 18 and 19 for controlling the supply of compressed air to the cylinders 13 and 1 1, and a pair of auxiliary or control drums 20 and 21 which are respectively coupled to the drums 3 and 4 of the controller and are provided with suitable contact fingers. The cylinders G, 7, 13 and 14 may form a single casting or may be separately secured to the base plate 5 upon which they are mounted, and the cylinder heads are preferably formed integral with the valve casings with which they are associated.

A yoke 22 is mounted on the cylinder casting and is provided with bearings 23 and 2 1; in which a shaft 25 of the auxiliary drum 20 is rotatively supported. Another yoke 26 is secured to the cylinder casting and is provided with bearings 27 and 28 in which a shaft 29 of the auxiliary drum 21 is retatively mounted.

The shafts 25 and 29 are respectively in substantial alinement with shafts 30 and 31 of the drums 3 and 1, to which they are operatively connected by couplings 32 and The coupling 33 is provided. with a crank projection 3 1 which is operatively connected to the piston rod 17 by means of a link 35. The arrangement of parts is such that, when the actuating windings of the valves 18 and 19 are energized, compressed air is admitted through the said. valves to the cylinders 13 and 1 1-, and, when the said windings are deenergized, the cylinders are open to the atmosphere and the air pressure within them is relieved.

The coupler 32 is provided with an annular toothed portion which constitutes a pin ion and meshes with the teeth of the rack upon one side of the connecting rod 10. The arrangement of parts is such that, when fluid pressure is admitted through the valve 11 to the cylinder 6 and fluid pressure is ex hausted through the valve 12 from the cylinder 7, the pistons S and 9 and the connecting rod 10 are so actuated as to produce rotative movement of the main drum 3 and the auxiliary or control drum 20.

The electromagnetically actuated valves 11, 18 and 19 are substantially alike and each of them is constructed as shown in Fig. 3 of the drawings. The valve 12 is, however, constructed as shown in Fig. 4 of the drawings. Each of the valves 11, 18 and 19 comprises a casting 39 having a vertically extending cylindrical chamber, a pair of apertured disks 37' and 38 having frustoconical valve seats located and spaced apart within the said chamber, a valve stem 42 having frusto-conical plugs 40 and 41 adapted to engage said seats, and a magnet com prising a coil 43, a stationary core member 44, which forms a part of the casting 39, and a movable core member or armature 45 which is secured to the valve stem 42.

The cylindrical chamber in which the disks 37 and 38 are located is divided thereby into an exhaustchamber 46 having an exhaust port 47, an inlet chamber 48 having an inlet port 49, and a pressure chamber 50 with which a passage 51 leading to the cylinder communicates. The lower end of the valve stem 42 is enlarged to form a frustoconical spring seat 52, and a plug 53, which closes the lower end of the cylindrical chamber, is provided with an opposing conical projection 54, a helical spring 55, which tends to force the plug 41 against its seat and to raise the plug 40 from its seat, being interposed between the members 52 and 54. 1V hen the coil 43 is energized, the armature 45 is moved downwardly to cause the plug 40 to engage its seat and the plug 41 to be released from its seat.

When the plug 40 is raised, the cylinder with which the passage 51 communicates is exhausted through the port 47, and when the plug 41 is lowered, fluid pressure is supplied from any suitable source (not shown) through the inlet port 49.

The magnet valve 12 shown in Fig. 4 differs from that of Fig. 3 in that its exhaust passage is normally closed and its admission passage is normally open. It comprises a casting 56 having a stepped cylindrical chamber which is divided into an exhaust chamber 57, a pressure chamber 58 and an admission chamber 59 by means of apertured disks 60 and 61 Having frusto-conical valve seats.

A frusto-conical plug 62 for the exhaust passage cooperates with the seat in the disk 60 and is normally held in engagement therewith by a spring 63, while another plug 64 is, by the same means, normally main- I tamed 111 a raised position and out of engage- In view of the foregoing, it is evident that if the actuating electromagnets of the valves 18 and 19 are both deenergized, atmospheric pressure will exist in the cylinders 13 and 14, and, accordingly, no movement of the pistons 15 and 16 or of the reverser and auxiliary drums 4 and 21 will occur, while if one is energized and the other is deenergized, the pistons, the connecting rod 17 and the link 35 will be moved away from the valve, the electromagnet of which is energized. In order, therefore, to actuate the reverser drum 4and the auxiliary control drum 21, it is only necessary to energize the actuating winding of only the valve in the opposite direction to that which it is desired to move the pistons 15 and 16.

Since the valves 11 and 12 are different in construction, that is, since the valve parts in the one are in inverse relation to those in the other, full pressure will normally exist in the cylinder 7, while pressure will be exhausted from the cylinder 6 when the actuating windings 01 both magnets are deenergized, and, therefore, the drum 3 and the control drum 20 will be moved into or held in their off positions.

In order to advance the said drums, it is only necessary to energize the actuating windings of both the valves 11 and 12, thereby introducing full pressure to the cylinder 6, and exhausting pressure from the cylinder 7. The drums may be stopped and held indefinitely in any position by merely deenergizing the actuating winding of the valve '12, while energy is supplied to the winding of the valve 11, or, in other words, by re storing full balanced pressure in the cylinders 6 and 7 The auxiliary or control drum 20, as hereinafter pointed out, is adapted to govern the energization of the actuating windings for the valves 11 and 12, while the control drum 21 is adapted to govern the enorgization of the windings of the reverser valves 18 and 19.

Referring to Figs. 5 and 6 of the drawings, which may be considered as a single diagram, the control system here shown comprises a positive supply circuit conductor 71, a negative line conductor 72, an automatic circuit breaker 73, a canopy switch 74, a line switch marked LS, the main con trol drum 3, the reversing drum 4, a pair of cut-out switches and 7 6, an accelerating resistor 77, a pair of electric motors having armatures A and A and field magnet winding F and F, a control circuit resistor 7 8, the auxiliary or control drum 20, the reversing auxiliary or control drum 21, a limit switch 7 9, an overload trip relay switch 80, a main master switch 81 and a reversing master switch 82.

The control circuit resistor 78 is connected directly between the supply circuit conductors 71 and '72, when a pair of switches 83 and 84 are closed.

The master reverser 82 is adapted to occupy positions a" and g and the master switch 81 is adapted to occupy an off position and a plurality of motor-operating positions 1 to 8, corresponding to the various positions of the main control drum 3.

Assuming that the master reverser 82 is thrown to position a: and that the master switch 81 is moved into position 1, a circuit is established from an intern'iediate tap 85 in the resistor 78, to a conductor 86, contact fingers 87 and 88, which are bridged by a contact member 89, a conductor 90, contact fingers 91 and 92 of the auxiliary reverser drum 21 which are bridged by a contact member 93, actuating coil 94 of the valve 18, a conductor 95, contact fingers 96 and 97, which are bridged by a contact member 98 of the master reverser 82, an emergency cutout switch 99, a conductor 100, contact fingers 101, which are bridged by a contact member 102, and a conductor marked 0 to substantially the middle point in the control resistor 78.

The coil 94 of the valve 18 being now energized, causes fluid pressure to be admitted to the cylinder 13 with the result that the reverse drum 4 and the auxiliary drum 21 are moved to the position m. In this position, the finger 92 is disengaged from the contact member 93 and, consequently, the coil 94 is deenergized sothat fluid pressure is released from the cylinder 13 in order that the reverser may be ready for subsequent operation in the opposite direction.

A circuit concurrently is completed from the conductor 90, through contact. fingers 103, which are bridged by a contact member 104 when the controller 20 occupies its oil' position, a conductor 105, a coil 106 of the line switch, the; trip relay switch 80, a conductor 107, contact fingers 108 and 109, which are bridged by a contact member 110 of the control reverser 21, the conductor 95, etc, to the conductor 0. The line switch is thus closed and a holding circuit is established for the coil 106 from the conductor 90, through the interlocking contact members marked LSin.

As soon as the line switch closes, a circuit is also established from conductor 90, through the interlocking contact members LS in, actuating coil 115 of the valve 11, and the conductor 107 etc., to the 0 conductor. By reason of the energization of the coil 115 of valve 11, fluid pressure is ad mitted to the cylinder 6. However, no movement of the pistons 8 and 9 occurs at this time because balanced pressures exist in the cylinders 6 and 7.

A connection is concurrently established from the conductor 90 through contact fingers 111 and 112, which are bridged by a contact member 113 of the auxiliary drum 20, a conductor 114, the limit switch 79, the actuating coil 117 of the valve 12, and conductor 107, etc., to the 0 conductor. Fluid pressure is consequently released from the cylinder 7, and the drums 3 and 20 are moved forward until the contact finger 111 becomes disengaged from the member 113. This occurs as soon as control. drum 20 occupies position 1. At this point in the operation, the coil 117 of the valve 12 is deenergized, thereby restoring balanced pressures in the cylinders 6 and 7 and holding the drums 3 and 20 in position 1.

Upon the movement of the drum 3, a motor circuit is established from conductor 71 through the circuit breaker 73, canopy switch 74, a conductor 116, the line switch LS, contact fingers 118 and 119, which are bridged by a contact member 120 of the controller 3, the accelerating resistor 77, one blade of the cut-out switch 76, a conductor 120, contact fingers 121 and 122, which are bridged by a contact member 123 of the reverser, a conductor 124, actuating coil 125 of the limit switch 79, armature A actuating coil 126 of the overload trip relay switch 80, a conductor 127, contact fingers 128 and 129, which are bridged by a contact member 130, a conductor 131, field. magnet winding F a conductor 132, contact fingers 133 and 134, which are bridged by a contact member 135, the other blade of the motor cut-out switch 76, and one blade of the cut-out switch 75, a conductor 136, contact fingers 137 and 138, which are bridged by a contact member 139, a conductor 140, armature A a conductor 141, contact fingers 142 and 143, which are bridged by a contact member 144, a condue tor 145, field magnet winding F a conductor 146, contact fingers 147 and 148, which are bridged by a contact member 149, conductor 150, the other blade of motor cutout switch 75 and a conductor 151 to the opposite line conductor 72.

The motors are thus connected in series relation, with the resistor 77 and the energizing coil of limit switch 79 included in circuit therewith. By reason of the completion of the main motor circuits, just recited,

energy is supplied to the driving motors which are accordingly started into operation and are accelerated up to a speed corresponding to the first position of the controller.

The acceleration of the motors will not progress so long as the master switch 81 remains in position 1, but if the master switch is moved successively through its positions 2, 3 and 4, the coil. 117 of the valve 12 is alternately energized and deenergized, and the drums 3 and 20 will move forward through the corresponding positions stepby-step, but dependent upon the action of the limit switch 79. Thus, the resistance of the motor circuit is gradually eliminated, thereby causing the motors to accelerate in speed.

The limit switch coil 125 is so designed as to lift the switch 79 when the motor current exceeds a predetermined amount and, consequently, the acceleration is sufliciently delayed to prevent injuring the motors. For instance, if the motor current exceeds the value for which the limit switch is adjusted,

7 further progression of the controller is prevented because of the interruption of the energizing circuit of coil 117 of valve 12 which causes the admission of pressure to cylinder 7 and holds the controller drum at rest. As soon as the current falls and permits the limit switch 79 to close,coil 117 is again energized and the valve 12 exhausts cylinder 7 and allows the piston 8 to advance the controller to its next step. Subsequently, the operation may proceed in accordance with circuit conditions and the will of the operator.

The controller 3 is adapted to effect a well known series-parallel control for the motors and need not be described in detail. As to the controller 20, the contact member 113 is so subdivided and arranged as to.

interrupt the circuit established through the coil 117 of the magnet valve 12 as each control position is reached. Each successive forward movement is thus dependent both upon the limit switches and the position of the master controller.

The contact member 102 is mounted on an insulating ring 152. that is connected to the drum of the master controller 81 by a friction clutch or similar connection and is limited in its rotative movement by a stationary pin or stop 153 which permits it to move only into engagement with the fingers 101. The arrangement of parts is such that when the master switch is moved into its position 1, the friction clutch connection carries the contact member 102 into engage ment with the fingers 101 and the stop 153' holds it in this position as long as the master switch progresses forwardly, but any backward movement of the master switch, whether it be from the position 8 or from some intermediate position, will move the contact member 102 out of engagement of the fingers and will break the circuit at this point. i

From the circuits above traced, it is evident that, as soon as the circuit is interrupted between the fingers 101, the line switch will be opened and the coils of the valve 11, 12, 18 and 19 will be de'elnergized,

While this will produce no movement of the reverser 21, it will throw the drums 3 and 20 to their off positions, as hereinbefore pointed out.

Obviously, the circuit connections of the system may be varied considerably and the operating head may also be greatly modified as to its structural features and may be em ployed to operate any form of drum controller or regulator, without departing from the spirit and scope of our invention, and we, therefore, do not wish our invention limited .to the specific details herein disclosed.

e claim as our invention:

1. In a control system, the combination with a plurality of electric motors, an accelerating resistor, a controller for arranging the circuits of said motors and said resistor for series and parallel operation, and electrically governed fluid-actuated means for effecting movements of said controller and embodying a movable piston, of a master controller for manually controlling the energizing circuits of said electrically governed fluid-actuated means, and an auxiliary control device associated with said motor circuit controller and having interlock contact members corresponding to each position of said motor circuit controller for intermittently making and breaking an energizing circuit of said electrically governed fluid actuated means to effect successive balancing and unbalancing of fluid pressures on the opposite sides of said piston to cause a stepby-step movement of said motor circuit controller through all of its positions.

2. In a control system, the combination with an electric motor, an accelerating re,- sistor, a main controller for adjusting the circuit connections of said motor and said resistor, and an electrically controlled fluidoperated device for actuatingsaid controller and comprising a movable piston, a cylinder therefor, and means for admitting fluid to one side of said piston and for releasing it from the other side thereof for actuating said controller, and for admitting fluid to both sides of said piston to arrest movements thereof, of means mechanically asso ciated with said piston for intermittently affecting said fluid-releasing means and causing a step-by-step .movement of said main controller.

3. In a control system, the combination with a plurality of electric motors, an accelerating resistor, a main controller for adjusting the circuit connections of said motors and said resistor for series and parallel operation, and an actuator for said main controller comprising a cylinder, a movable piston, and electrically controlled valves at each end of said cylinder for admitting and releasing an operating fluid to and from said cylinder, of a manually operated master controller for governing the circuits of said electrically controlled valves, and an auxiliary control device mechanically associated with said main controller for governing the operation of said electricallv controlled valves.

4. In a control system, the combination with a plurality of electric motors, an accelerating resistor, a main controller for adjusting the circuit connections of said motors and said resistor for series and parallel operation, and an actuating device for said controller comprising a cylinder, a movable piston, and electrically controlled valves governing the admission and release of an operating fluid at the respective sides of said piston, of a manually operated master controller and an auxiliary interlock controller associated. with said motor circuit controller for alternately ener izing and deenergizing certain of said valves for effecting a: stepby-step movement for said main controller.

5. In a control system, the combination with a plurality of electric motors, an accelerating resistor and a main controller for arranging the circuits of said motors and said resistor for series and parallel operation, and an actuating mechanism for said controller comprising a piston, a cylinder and valve magnets for governing the admission and release of fluid to and from the respective ends of said cylinder, of an auxiliary controller operatively connected to said main controller for successively deenergizing certain of said valve magnets in each position of said main controller for effecting successive steps through all of its positions, and a master switch cooperating with said auxiliary controller for governing the operation of said magnet valves.

6. In a control system, the combination with an electric motor, an accelerating resistor, a main controller for adjusting the circuit connections of said resistor, and an actuating device for said controller comprising a cylinder, a movable piston, and electrically controlled valves governing the admission and release of an operating fluid at the respective sides of said piston, of means governing the circuits of said electrically controlled valves, whereby one thereof is continuously energized to admit fluid pressure to one end of said cylinder and the other is concurrently energized to permit a forward movement thereof and is deenergized to stop said forward movement, and an auxiliary control means in circuit with one of said electrically controlled valves for effecting a step-by-step movement of said main controller 7. A controller comprising a main rotatable contact-bearing drum adapted to occupy a plurality of positions, a rotatable reverse drum adapted to occupy two positions, and electro-pneumatic means embodying a movable piston for actuating the main drum step-by-step through the continued application of a pneumatic medium and successive balancing and unbalancing of fluid pressure on opposite sides of said piston and for throwing the reverse drum from the one to the other of its operating positions.

8. A controller comprising a main rotatable contact-bearing drum adapted to occupy a plurality of positions, a rotatable reverse drum adapted to occupy two positions, and electro-responsive means for actuating the main drum step-by-step and adapted, when deiinergized to return the main drum to its off position and electro-responsive means for actuating the reverse drum.

9. A controller comprising a main rotatable contact-bearing drum adapted to oc cupy a plurality of positions and a rotatable reverse drum adapted to occupy two positions, of a pair of pistons operatively connected to the main drum, cylinders co operating therewith, electro-magnet valves for governing the admission of fluid to the cylinders and corresponding actuating mechanism for the reverse drum, the valve magnets of the main drum being dissimilar and the valve magnets of the reverse drum being similar to each other.

10. A controller comprising a main rotatable contact-bearing drum adapted to occupy a plurality of positions and a rotatable reverse drum adapted to occupy two positions, of a pair of pistons operativcly connected to the main drum, and cylinders cooperating therewith, a pair of pistons operatively connected to the reverse drum and cylinders associated therewith, and electromagnet valves for the several cylinders, the valves associated with the cylinders of the reverse drum and one of the cylinders of the main drum being open when deenergized to admit fluid to the cylinders, and the other magnet valve of the main drum being closed when deiinergized to exhaust fluid from the cylinder with which it is associated.

11. The combination with a main control drum, and a reverser control drum, of auxiliary interlock drums associated with said main and said reverser drums, and electrically controlled fluid-actuated means mechanically associated with said main control drum and reverser control drum and having energizing circuits electrically controlled by said auxiliary interlock control drums.

12. The combination with a controller comprising a main control drum and a reverser control drum adapted to occupy a plurality of positions, of an electrically con trolled power-actuated mechanism disposed above said controller and adapted to inde pendently actuate the respective control. drums and embodying auxiliary interlock control drums respectively mechanically associated with said main control drum and said reverser control drum and adapted to govern the energizing circuits of said electrically controlled power-actuated mechanism.

13. The combination with a controller comprising a main control drum and a reverser control drum adapted to occupy a plurality of positions, of a plurality of independently electrically controlled pneumatically actuated devices respectively associated with the main control drum and the rcverser control drum and. adapted to actuate said drums, and a plurality of interlock control drums respectively associated with said main control drum and said reverser control drum for independently governing the energizing circuits of said independent electrically controlled pneumatically actuated devices.

14. The combination with a controller having a main rotatable contact-bearing drum adapted to occupy a plurality of posi tions and a rotatable reverser drum adapted to occupy two positions, of electrically controlled fluid-operated means and auxiliary interlock control drums associated with said main drum and said reverse drum for actuating said main drum step-by-step and for actuating the reverse drum from the one to the other of its operative positions.

15. The combination with a controller having a main rotatable contact-bearing drum adapted to occupy a plurality of positions and a rotatable reverser drum adapted to occupy two positions, of a pair of pneumatic actuating devices severally connected to said main drum and said reverser drum and each embodying a plurality of electromagnetic valves for governing the admission and release of operating fluid to and from said device, and an auxiliary control drum associated with said main drum for control ling the energizing circuit of one of the associated electro-magnetic valves to effect a step-by-step movement of said drum and a second interlock control drum associated with said reverser drum for deenergizing the associated electro1nagnetic valves of said reverse drum operating device in either of its two operative positions.

16. The combination with a plurality of controller drums, of a removable operating head associated therewith and comprising a fluid-actuated member associated with one of said drums and embodying means for effecting a step-by-step movement thereof, and a second fluid-actuated means associated with other drum for effecting its actuation.

17. A unitary control device comprising a casing, a plurality of control drums disposed therein and a plurality of fluid-actuators mounted upon said casing, and severally connected to said control drums, one of said actuators being provided with dissimilar lable valves, both valves of one actuator and one valve of the other being alike, and the remaining valve being different in construction.

19. The combination with a casing, a control drum substantially centrally positioned, an offset control drum disposed therein, and a plurality of fluid-actuated devices mounted in parallel relation upon the end of said casing and severally comprising a cylinder, a pair of connected pistons and valves at the ends of the cylinder, of a rackand-pinion connection between one of said control drums and a point intermediate the connected pistons of one of said fluid-actuated devices and a connecting link between the other control drum and a point intermediate the connected pistons of the other fluid-actuated device.

20. The combination with main controlling means, of a fluid-operated head comprising auxiliary control means, a gear pinion operatively connected with said main controlling means, a rack meshing with said pinion, a piston associated with said rack, a cylinder in which the piston operates, and controllable valves associated with the respective ends of said cylinder, one of said valves being normally open and the other normally closed.

21. The combination with a controller drum, an inclosing casing therefor, and a shaft for said drum projecting through said casing, of a fluid-actuator removably mounted upon said casing and coupled to said shaft and comprising a piston, a cylinder, electrically operated valves in the respective ends of said cylinder, and interlocking control means associated with said piston for governing the energizing circuit of one of said valves.

22. The combination with a controller having a plurality of operating positions, of a fluid-actuator associated therewith embodying a cylinder and a movable piston for actuating said controller in a series of definite steps through the continued application of a fluid-medium and the successive balancing and unbalancing of fluid pressures on the opposite sides of said piston.

In testimony whereof, we have hereunto subscribed our names this 25th day of Sept,

NORMAN W. STORER. ARTHUR J. HALL.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, I). 0. 

